There was a shorter latency of the reflex loop delay in patients with SCI in this study, which could be due to heightened state of spastic muscles with quicker development of muscle force and/or due to reduction in the presynaptic inhibition between Ia afferent and α-motoneurons under altered upper motor neuron control.
There was also a significant reduction in muscle force, likely due to an energy metabolism imbalance and decreased oxidation, in both fast and slow types of skeletal muscle fibres [11].
Further, the non-rigidity of tendons allows the storage and return of strain energy during locomotion [4,5] and facilitates the muscle force potential due to the force-length-velocity relationship [6-8].
Glucocorticoids, induce acute myopathy within a few days and reduce muscle force predominately due to atrophy of type II muscle fibers, without affecting specific muscle force [ 24].
However, the specific force of individual fibres also declines with age [9], [34] [35], suggesting that the loss of muscle force is also due to factors intrinsic to the muscle fibres themselves.
All adherent structures of the transporting bone segment such as tendons, fasciae and muscles generate a force due to the distraction of the soft tissues.
There was also general agreement that older persons may be weak for reasons other than low muscle mass, because the muscle is not producing adequate force due to factors either within or outside the muscle itself.
In all our measurements we could clearly identify three sources of noise: A high-frequency, low-amplitude signal that we refer to as measurement noise, meaning that it is probably not part of the muscle force, but is rather due to our recording system.
It is probably more important for elderly to recover function as fast as possible since bone mass density, proprioception and muscle force already are decreased due to the higher age.
Studies that carefully controlled posture and trunk kinematics did not find any significant reduction in muscle activity or spine compression force due to a LSO [ 3, 22, 23].
